Black Headed Gulls. In the summer the adult has a chocolate-brown head (not black, although does look black from a distance), pale grey body, black tips to the primary wing feathers, and red bill and legs. The hood is lost in winter, leaving just 2 dark spots.
In the 1990s, local Broome birder Brian Kane saw a strange species of bird while trawling the local sewer ponds. Upon seeing this bird, he called one of his many bird-watcher friends to verify the species, who confirmed that it was indeed a Black-headed Gull that Brian had stumbled across. This was the first recorded sighting of the species in Australia.
Ian